1. Field of the Invention
The present invention relates to a film feeding apparatus for automatically feeding a film to the outside of the reel on which the film has been rolled round.
2. Description of the Prior Art
Long film sheets, such as microfilm, magnetic tape and movie film (hereinafter these long films are referred to generically as "film"), have difficulties in handling and storage. To overcome these difficulties in these years there has been widely used a so-called cartridge in which a film is received in the form of film roll. Such a cartridge containing a film roll is used in various apparatus, for example, in microfilm reader, magnetic recorder and reproducer, photographing apparatus, projector, etc. In connection with the use of film cartridge in these apparatus, there is an increasing demand for automatic film loading apparatus, automatic film feeding apparatus and the like.
As an automatic film feeding apparatus there has been already known a system in which a film rolled round a reel is fed automatically from the reel to the outside of the reel in the following manner:
A leader part having a larger width than the image recording part of the film is affixed to the forward end of the film. The film is rolled round such a reel which has a pair of flanges spaced from each other by a distance smaller than the width of the leader part. Because of the larger width of the leader part, the winding of the leader part is on the outer circumference of the paired flanges. A feed roller is brought into contact with the winding of the leader part and then driven into rotation. Owing to the frictional contact between the feed roller and the leader part, the latter is fed automatically from the reel to the outside thereof by the rotating feed roller.
In this type of known automatic feed apparatus, the feed roller starts to rotate and is also brought into contact with the winding of the leader part on the flanges of the reel by applying a start instruction. The leader part fed from the reel by the feed roller is guided, for example, to a take-up reel which is also driven into rotation to take up the leader part. After almost all of the leader part has been taken up on the take-up reel, the remaining part of the film is fed from the supply reel solely by the rotation of the take-up reel. Therefore, in this apparatus, the feed roller should be stopped and moved to its retracted position apart from the supply reel in good time after the leader part has been taken up on the take-up reel. In the retracted position, the automatic feed apparatus becomes inactive.
In the known apparatus, in order to retract the apparatus to the inactive position, there has been provided detection means such as a microswitch in the film feeding path. Whether or not any portion of the leader part is present in the feeding path is detected by said detection means such as the microswitch. According to the prior art, the automatic feeding apparatus is retracted to the inactive position when there is no longer present any portion of the leader part to be detected. However, this prior art detection method involves some problems, such as the film is contacted by said detection means such as microswitch and therefore the film is damaged. It has been found that when a film is used employing such a known automatic feeding apparatus for a long time, the film and therefore the images recorded on the film may be finally broken.
Another method provides a take-up detection means for detecting that the leader part has just been taken up on the take-up reel. When it is detected, said detection means issues a signal by means of which the automatic feeding apparatus is retracted to the inactive position. However, this method also has a drawback in that it makes the apparatus very complicated.